Printing slanted text

While Mup doesn't have a command for directly printing text at some
particular angle, it does allow printing text above a line, and that line can
be at an angle. The original intent was to use that for
printing "glissando," but it can be used for other things too.
So to print arbitrary text at an arbitrary angle,
you can make the line so tiny it can hardly be seen.
Because of roundoff, it is generally not possible to make it so small
that you can't see it at all, but it can be small enough to look like
just a stray ink dot. By adjusting the relative location
of the endpoints of the tiny line, you can control the angle.